Digital printing machine

ABSTRACT

The invention concerns a digital printing machine for sheet printing with a digital printing mechanism with free format in the peripheral direction, an intermediate cylinder which is connected downstream of the digital printing mechanism and is at least partially coated with an elastic material, and a counterpressure cylinder which is connected downstream of the intermediate cylinder, wherein the counterpressure cylinder has grippers holding the sheet and the intermediate cylinder periphery is provided with recesses for receiving the grippers.

This application is the national stage of PCT/EP03/007656 filed on Jul.15, 2003 and also claims Paris Convention priority of DE 102 32 864.1filed on Jul. 16, 2002 and DE 103 12 870.0 filed on Mar. 18, 2003.

BACKGROUND OF THE INVENTION

The invention concerns a device for indirect digital front and back sideprinting of multicolored pictures onto sheets using single shot andsingle pass methods.

Packaging and label printing are currently growing markets. Thepackaging market is expected to double within the next five yearsthrough the influence of Eastern Europe, South-East Asia and China,wherein plastic materials, sandwich materials and metallized substrateswill be increasingly used. The worldwide turnover with packagingprinting machines is about one billion Euros (Deutsche Drucker No. 4 ofFeb. 6, 2003).

The packaging market poses the highest demands concerning printing andfinishing quality. In jobbing (commercial), almost everything is printedwith standard process colors, optionally extended by a customer-specificpantone color. In packaging printing many more pantone colors are used,either exclusively or as a supplement to the process colors.

Conventional sheet-fed offset machines are classified by the maximumprintable sheet format in accordance with format classes with thefollowing variants:

Small format  353 × 500 (B3) Semi-format  500 × 707 (B2) Medium format 707 × 1000 (B1) Large format 1000 × 1414 (B0)

In conventional sheet printing machines in accordance with the offset orbook printing method, picture-carrying plates are used in dependence onthe format class, which must be exchanged when the motive or orderchanges. The illustrating or plate cylinders comprise a tensioningchannel, which is also format-dependent, and mostly comprise demandingsemi-automatic plate exchange systems.

For printing, it is standard to add a particular customer-specific colorto the four process colors cyan, magenta, yellow and black (C, M, Y, K).The CYMK color space is likely to preclude readjustment of the pantonereference value. To obtain a larger color range for multi-colorprinting, complementary red, green and blue (R.G.B) are additionallyincreasingly used for the 7-color HIFICOLOR system or the additionalcolors orange and green are used for 6 color hexachrome systems. This isadvantageous in that 95% of the pantone colors can be printed withoutrequiring the hitherto associated time-consuming cleaning of theprinting mechanism for a new order. This is also confirmed by theincreasing application of sheet-fed offset machines with 8 and 10printing mechanisms, not only for double-face 4-color printing but alsofor matrix printing with additional colors for this so-calledHigh-Fidelity print.

The color is transferred indirectly from the printing plate to thematerial to be printed via the (exchangeable) rubber blanket therebycompensating for unevenness of the material to be printed. Surfaces andmatrix points are transferred almost as if the material to be printedhad an ideal flat surface which permits processing of a large range ofprinting materials.

This also prolongs the service life of the illustrating cylinders, thetransfer band or the transfer drum, since they are not in direct contactwith the abrasive surface of the printed material.

The system is very precise (±0.1 mm) since the substrate sheets arealigned through side and front lay marks when the system is stopped.

The printed sheets are transferred from the feeder pile to the firstprinting mechanism, from printing mechanism to printing mechanism andfrom the last printing mechanism to the delivery pile using grippingtechnology which is integrated in the counterpressure cylinder channelor in a chain carrier, in dependence on the format. This means that theseparation between a gripper system and the neighboring gripper systemis always equal to the maximum printing format in the peripheraldirection.

Flexo lacquering mechanisms with fixed format are increasinglyintegrated in printing machines, since application of a lacquer layerconsiderably increases the quality of the prints, e.g. protects theprinted material and improves further printing processing or e.g. spotlacquering for optical effects.

A further development concerns application of a primer (with primer inthe Flexo method) before and after printing e.g. for printing plasticmaterials with hybrid printing systems, i.e. the combination ofdifferent printing methods in one printing machine (U.S. Pat. No.6,443,058 B1).

NIP methods for personalization (DE 100 47 040 A1), punching units (DE101 47 486 A1) for further processing, embossing units for hapticeffects (Look and Feel) and Inline Finishing (EP 80 929 091 A1) e.g. forfolding have recently been integrated in the chain of processconsolidation. The above-described combination of high-quality printing,finishing and further processing methods also requires relativelydemanding drying systems which results in machine lengths of up toapproximately 35 meters, as reported in Druckspiegel No. 5, May 2002 SMType CD 102 LY-6-LYYLX of the company Thomas in Gelsenkirchen as well asby COMPRESS Magazin on Apr. 6, 2003, concerning a KBA Rapida 142sheet-fed offset machine having a format of 102×140 and a length of 37.5meters in Illinois (USA). This machine comprises 7 offset printingmechanisms, one lacquer printing mechanism, intermediate drying and lastprinting mechanism, including a turning device. These highly demandingmachines require i.a. expensive automation and drive concepts with e.g.double drives having toothed wheel tension and cardan shafts as well asseveral intermediate and final dryers (DE 199 12 309 A1). Without suchdevices, this technology could not be mastered.

Sheet turning systems are also often integrated in the sheet printingmachines to print both the front and the back sides in one process.

For the above-mentioned reasons, a great amount of space is requiredwhich poses substantial problems, i.a. to a desired one-man operation,and involves new investment for the extension of the premises. Inconventional applications, compact machines of satellite structure areused for small formats, with the number of printing mechanisms beinglimited to 4. For small, semi-, medium and large formats, modularstructures for series construction are therefore frequently used whichhave their own construction module for each printing mechanism.

For both conventional machine concepts, format-related conventionaloffset or letterpress plate cylinders having tensioning channels areused. FIGS. 15 and 16 show that the use of 2×7 printing mechanisms ofhalf-size portrait (with 345 mm diameter) would produce ergonomicallyunrealistic dimensions with this concept and for modular as well assatellite structures, additional modules, e.g. roll unwinding or forfinishing or for further processing, are also unrealistic.

In view of the technical effort of conventional printing technologies,and due to the fact that one expects, due to the influence of “POD”(print on demand) or just in-time production, that 90% of all jobbingand a considerable part of packaging printing orders will involve lessthan 5000 sheets, it becomes clear that other printing machine conceptsmust be invented to ensure economic future production.

For digital printing machines, a nearly offset-like quality with maximumflexibility is generally obtained in prior art, since each sheet can becontinuously printed with another motive if required without losing timefor adjustments and without having to change plates. To optimallyutilize the data processing speed, the digital printing machines aredesigned for portrait format processing. The digital printing methodrequires no demanding radiation and dryer systems, thereby facilitatingprocessing consolidation with additional processing steps. For thisreason, the digital printing method is well suited for printing smallruns of small formats (currently max. A3 format, approximately 330×460mm).

Most digital printing machines have paper transport systems e.g. usingtransport bands (DE 195 36 309 A1). Grippers are not used for transferof the sheet (except for WO 96/17277). This limits the precision of thecolor register required (±0.01 mm) and the feed register (±0.1 mm). Thetolerances of the feed and transfer passers (color register) aregenerally larger by approximately a factor of 2 to 4 compared toprinting methods using conventional feeding and gripper technology suchas e.g. sheet-fed offset printing. These large tolerances (image drift)in digital printing require complicated systems to compensate for, or toattempt to compensate for, these tolerances (image drift) in inlinefinishing.

More digital printing machines must be used which are suitable for thePOD market. The limited technical features preclude use in the graphicsindustry (Report Pira International Ltd. 2002 ISBN 185824641). Digitalmachines without grippers are mainly limited by the maximum format size,production speed, flexibility of the material to be printed and feedpasser.

It is therefore the object of the invention to develop a new generationof printing machines to meet the new market demands for maximum qualitywith minimum copies for POD and just in time systems, wherein theadvantages of the conventional sheet-fed offset technology and newdigital technology must be utilized to ensure future economicalproduction. The requirements are listed below:

-   1. 1 to 7 digital printing mechanisms with upstream cleaning station    for hexachromes or Hifi color print, using single shot and single    pass methods;-   2. integrated finishing with protective lacquer (100% of the    packagings require protective lacquer on one side) and alternatively    full-surface lacquer finishing for jobbing printing mechanisms    and/or special spot effect lacquer (approximately 20 to 30% of the    orders of a jobbing print are lacquered);-   3. the possibility of personalization or printing of variable data;-   4. indirect print through exchangeable rubber blankets to compensate    for unevenness in the material to be printed;-   5. a format class which is larger than the small format    (approximately 36×50 cm), preferably a 50×70, 70×100 format;-   6. the possibility of printing plastic material and sandwich    substrates;-   7. full-format duplex print on front and rear side without turning    and at full production speed (for jobbing prints approximately 90    duplex is printed and for packagings approximately 5 to 10 is    printed and/or finished. (e.g. rear side print with instructions,    safety features or protective lacquer or coating for the inside of    the packaging);-   8. uniform printing methods for printing, coating and finishing to    permit automation and reduce the requirements for operator skill;-   9. high-quality sheet alignment and gripper sheet transport systems    for feed and transfer passers, similar to sheet-fed offset, with    minimum gripper change or gripper transfer;-   10. high-quality arrangement of the printing cylinders preferably    with counterpressure cylinder of twice the periphery and delivery    arrangement in the so-called 7-o'clock position to permit perfect    undistorted printing (tangent function);-   11. high-quality arrangement and drive of the printing cylinders for    extremely high register accuracy on one side for multi-color print    and also between front and rear side print.-   12. Straight (minimized) sheet guidance for maximum flexibility of    the material to be printed and for separating the sheet from the    rubber blanket cylinder with minimum force;-   13. Stability with minimum operating oscillation for optimum    printing quality despite tensioning channels in the intermediate or    rubber blanket cylinder for use of novel liquid toner, which    requires more pressure than dry toners;-   14. Sheet guidance without blotting;-   15. Good accessibility of the individual machine elements;-   16. Inline finishing with exact register through gripper transfer    such as e.g. hot foil embossing and/or punching and/or piling or    inline folding or inline book binding;-   17. Complete utilization of the synergy of common parts, modules and    software of a family of printing machines for inexpensive mass    production;-   18. One size for one-man operation, preferably one machine length of    a maximum of approximately 7 m and a machine height of a maximum of    approximately 2.75 m.

U.S. Pat. No. 5,016,056 discloses principal prior art which is not basedon indirect print transfer via an intermediate carrier or rubber blanketcylinder. Printing is effected directly from the illustrating cylinder.This lacks the advantages of indirect printing via rubber-coatedintermediate cylinders, in particular, advantageous printing on unevensubstrate surfaces and the associated increased flexibility with respectto the material to be printed.

CH 116 828 describes conventional offset printing mechanisms withformat-dependent plate and rubber blanket cylinders which therefore bothhave tensioning channels. A 2×7 color printing machine of medium formatis excessively large for both a satellite as well as a modulararrangement (FIGS. 15 and 16). Change of motif requires demanding platechange and in most cases rinsing of the printing mechanism for othercustomer-specific pantone colors.

Neither does DE 100 47 040 A1 discuss digital printing mechanisms,rather offset printing mechanisms which are digitally exposed online,however, using conventional plate and rubber blanket cylinders which areformat-dependent and have the above-mentioned disadvantages.

DE 21 15 790 A1 also describes conventional offset and/or letterpressprinting i.e. with format-related plate cylinders having tensioningchannels and the above-mentioned disadvantages.

DE 199 12 309 A1 provides an example of a machine of modular structure(U.S. Pat. No. 6,443,058 B1) which is excessively long (approximately 25m). DE 100 47 040 A1 suggests a satellite arrangement with only 4printing mechanisms and a connected printing mechanism with couplingmeans required therefor. This machine disadvantageously requires asecond passage for the second print (approximately 90–95% of the jobbingprints are front and back side prints) and is also not suited for 7color print with subsequent finishing.

DE 21 15 790 A1 describes a construction or printing machine concept,which permits duplex printing in one process but which is a combinationof format-dependent plate imaging systems combined with conventionalformat-dependent rubber blanket cylinders. This construction does notpermit integration of up to 2×7 printing mechanisms or even furthermodules for coating without creating unacceptable handling andengagement problems (FIG. 15). This factor is of particular importancesince conventional digital printing mechanisms are based on portraitprinting (i.e. printing of a page in a vertical orientation), incontrast to landscape printing in conventional sheet-fed offset printing(i.e. printing of a printed page in a horizontal orientation). Moreover,additional space must be reserved for format-related illustratingcylinders or drums for access, e.g. for plate and/or rubber blanketreplacement. For this reason, the maximum satellite arrangement isconsidered to be 4 printing mechanisms (DE 43 03 796 A1). CH 116,828also discloses plate and rubber blanket cylinder constructions withbound format for tensioning imaging plates and rubber blankets. Theformat-related technology does not permit extension to 2×7 printingmechanisms with cleaning systems or even additional mechanisms forfinishing.

Conventional satellite printing machines (WO 01/39976 A1) do not takeinto consideration the above-mentioned requirements of digital printingwith regard to format-independent illustrating cylinders. Illustratingcylinders of fixed format are used which therefore cannot utilize theconsiderably compact construction of the inventive machine.

U.S. Pat. No. 5,016,056 discloses sheet transport without formattedgripper systems and avoids use of highly precise sheet gripper transportsystems with projecting gripper backs which would damage theillustrating cylinder, by using a vacuum strip which holds the sheet onthe feed side without protruding. The production tolerances of the feedpasser can be expected to vary by a factor of between 2 and 4—larger forthe sheet feed and transport system than for printing methods usingconventional gripper technology. Moreover, such systems without grippersare limited with respect to the flexibility of the material to beprinted, the sheet format and the sheet thickness of the printingsystem. The ends of the sheet are also held by vacuum. This isdisadvantageous in that only sheets of a fixed peripheral length can beprinted (“secures the ends of a receiving sheet”).

DE 195 36 359 A1 discloses an endless transport without gripper systems,wherein feed and transport passer tolerances must be expected which area factor of 2 to 4 times larger than for sheet feeder and transportsystems using conventional gripper technology.

CH 116,828 provides duplex printing in one step but only at half theproduction speed since “a sheet must be supplied at least after everysecond rotation”.

In known satellite printing machines with gripper transport devicesaccording to DE 43 03 796 A1, the number of rubber and plate cylinderpairs disposed about a printing cylinder is limited to four due to theneed for access to the printing mechanisms. Front and back side printing(duplex print) therefore require sequential arrangement of two printingmechanisms or twin stations which must be connected via a turning unitas also provided e.g. in U.S. Pat. No. 5,660,108 and DE-PS-435 902.

There are various conventional concepts of digital printing mechanismsfor duplex printing (front and rear side printing) e.g. via a turningpocket (U.S. Pat. No. 5,552,875) (which includes the risk ofdistortions, paper jamming, damage, halved productivity, for limitedthicknesses and is not that precise), twin installation (associated withinflexibility, large investment and many gripper transfers) or systemswith half the width or half the circumference.

Turning systems are known for sheet printing machines (DE 298 07 663 U1)for printing the first and second side of the sheets (recto verso).These systems are demanding, render the machine inflexible due to theirfixed position, are expensive and require a white edge (gripper edge) onboth sides of the sheet. Moreover, the registering sheet guidance(turning passer) is extremely difficult and leads to inaccuracies. Italso limits the flexibility of the printing material with regard tosubstrate thickness.

For applications which only require occasional duplex printing, it is,however, feasible to integrate a conventional turning drum system,wherein the above-mentioned disadvantages must be accepted.

EP 819 268 B1 discloses a digital printing mechanism using the so-calledmulti-pass system, wherein the intermediate cylinder passes severaltimes through the same printing gap and transfers the multicolored imageformed on the rubber blanket cylinder onto the printing material whenthe sheets are supplied in cycles during the so-called single shotprocedure. The associated efficiency is therefore very poor. Themultiple transfer on the intermediate cylinder could have negativeeffects on the register accuracy e.g. through slight bulging/speeddifferences during multiple passage of the printing gaps. Theillustrating cylinder is designed for replaceable plates or cylindermilling and has a tensioning channel for tensioning or holding theplate. The so-called photo imaging plate must be regularly replaced dueto wear. This construction is bound to a format and for this reasoncannot receive more than 4 printing mechanisms when used in a satelliteconstruction due to access needs (replacement of plate and rubberblanket) (DE 43 03 796 A1).

U.S. Pat. No. 6,363,234 B2 discloses a satellite construction withformat-related printing mechanisms/print engines which are limited to amaximum of 4 for access reasons. A special turning technique cuts theproductivity in half.

The photo conductor drum or illustrating cylinder 52 (FIG. 5), on whichthe toner image is formed from the charge image derived from the opticalimage, is the central component in the electro-photographic process.

FIG. 1 shows how the partial colors formed by the individual photoconductor drums S are collected on the rubber blanket segments beforebeing transferred to the printing material (single shot).

Partial colors can also be transferred onto a conducting rubber-likesilicon transfer band (FIG. 22) or transfer drum (FIG. 23) or onto acommon photo conductor drum and then onto an intermediate cylinderhaving rubber blanket segments to transfer the collected partial colorsto the printed material.

There are a plurality of digital printing techniques for transferringvariable data with color onto the material to be printed. The best knownmethods are inkjet, thermo transfer, thermo sublimation, electrophotography, magnetography, ionography and direct imaging technology(U.S. Pat. No. 3,846,840).

Digital printing with gripper sheet transport is not possible, since thetransfer band would be damaged by direct contact with the projectinggrippers, similar to the photo conductor drum.

It would be feasible to design the rubber-like silicon transfer band ortransfer drum or common photo conductor drum to be compressible in orderto compensate for unevenness of the substrate, such as for a rubberblanket. If these parts are delivered with format-dependent recesses forthe gripper backs, they could be disposed directly on a counterpressurecylinder with gripper transport system (not shown). Bands are, however,not as precise as drums and are moreover limited in length and maximumproduction speed.

SUMMARY OF THE INVENTION

In the inventive machine concept, the special properties of the photoconductor drum is utilized in an innovative fashion in that it must notcoincide with the printing length. The drum diameter may be smaller thanthe printing length would require, wherein the drum (without tensioningchannel) must be imaged through 360° drum rotation to print one page.These photo conductor drums or illustrating cylinders having aperipheral length which is less than the printing length, are ofsatellite construction with a collecting cylinder or intermediatecylinder having a number of replaceable segmented elastic printingblankets which are regularly disposed about the periphery of theintermediate cylinders, in dependence on the format size. This featurepermits very compact innovative construction using gripper sheettransport systems for multi-color Hi-fi printing on the front and rearsides in combination with multiple application of lacquer and with orwithout inline further processing in one production step (so-calledsingle pass system) with absolutely minimum adjustment times, optimumergonomic operating conditions (very small footprint) and inexpensiveproduction and operation.

This single shot system, wherein all partial colors and coatings such ase.g. lacquer are transferred at once from the intermediate cylinder tothe substrate, like e.g. lacquer, is also particularly advantageous forprinting sensitive substrates. When such substrates are printed withpartial colors by passing through several printing mechanisms, thesubstrate material can expand and thereby cause printing passerinaccuracies.

The inventive satellite printing machine has an intermediate cylinderwhich is formed as rubber blanket cylinder and which can be disposedcentrally (see FIGS. 1 or 2) and having at least 1 to 10 associatedsatellite printing mechanisms for front side printing disposed, in thedirection of rotation, between the supply system comprising a supplycylinder or supply rollers and the discharge system, and can cooperatewith another 1 to 10 satellite printing mechanisms for back sideprinting. This machine construction allows one-color or multicoloredfront side printing and/or back side printing on sheet-shaped printingmaterial which can be printed in one run and without additional turningtechnology.

In a preferred embodiment, the printing machine may be adjusted tovariable thicknesses of the material to be printed via radial adjustmentof the supply, printing, intermediate and discharge cylinders (arrow Y).

The compact construction of the satellite printing machine permitsprinting with uniform feed through conditions for the printing materialwhich precisely passes the intermediate cylinders, appropriatelyregistered through adjustment at standstill using conventional side andfront lay marks. For this reason, the inventive satellite printingmachine can achieve high cycle times and full printing speed in sheetprinting, leading to high printing quality with little adjustment time.This system permits full-format printing of the front and back sideprinting width of the printed sheet, wherein only one edge strip isrequired for the gripper which cannot be accessed by the printingsurface of a plate cylinder periphery. This considerably reduces paperwaste. The satellite printing machine can therefore also be used forprinting material which is difficult to handle such as e.g. cardboard,plastic materials, multi-layer packagings or the like. This process iscarried out without turning the sheets thereby obtaining more accurateregister (passer) tolerances.

A further aspect of the invention consists in finding a novel solutionfor a digital lacquer application/coating system in a single passdigital printing, partial color transfer system which is not bound to aformat, i.e. without using another printing method, since theseconventional hybrid machine concepts pose high requirements with respectto operation, cannot be automated through digital workflow, and alsohave the disadvantage that they are bound to a format as is aconventional sheet-fed offset machine. Additional dryers are alsorequired. The inventive solution permits coating with a (liquid) lacquertoner without pigments. This step can be included in a digitalapplication form (job ticket), such that processing consolidation can befully automated.

In a further aspect of the above-mentioned invention, the lacquer isapplied to the intermediate carrier as a first coating, wherein thepartial colors are subsequently transferred and printed on the printingmaterial in the form of multiple layers, in one printing step (singleshot). This (dry or liquid) toner without pigments obtains its shinethrough contact-less and/or mechanical conditioning. The lacquer is usedas full-surface protective lacquer and/or as partial spot lacquer. Thelacquer coating can also be used as a primer. This lacquer layer couldalso be used as white lacquer for printing transparent substrates. Thislacquer layer can also be used with a so-called UV lacquer for optimumhardness to protect the material to be printed.

In an alternative inventive embodiment, inexpensive imaging cassettesare used only for printing or coating motifs which do not permanentlychange, e.g. for full-surface support lacquer or full-surface priming.

These inventive digital imaging cassettes are designed like a flexoletterpress printing mechanism with anilox roller and chamber doctoringsystem. The so-called E-anilox roller, a particular type of photoconductor drum, is adjusted for full-surface application of powder orliquid toner without pigments. In contrast to imaging cassettes forcontinuous variable imaging, these cassettes have a fixed format. Themotive or image change can be carried out only through a slightly moredemanding application format change. The construction costs areconsiderably reduced since no demanding electronic control is requiredfor protective lacquer and primer applications which are principallyalways full-surface applications. Format-free E-anilox cassettes wouldalso be feasible.

In an advantageous embodiment, the cylinder or chain transfer followingthe counterpressure cylinders is disposed in the so-called 7 o'clockposition such that transfer takes place only after printing the entiresheet format to prevent the so-called tangent function during wrapping,i.e. acceleration and the associated print distortion. The 7 o'clockarrangement can be handled despite the compact dimensions of themachine, which are ergonomically specified, and the “lean” sheetguidance defined by the maximum printing material thickness.

In an advantageous embodiment, the illustrating cylinders each formcassette-shaped construction units (so-called cassette inserts), with orwithout their toner supply systems for the satellite printing mechanismsof the machine, which can be displaced from their working position intoa service position, towards the operation or drive sides. This permitseasy and fast adjustment to changed printing conditions, e.g. new tonercontainers, illustrating cylinders or cleaning systems, despite densesequential arrangement of the satellite printing mechanisms andconditioning systems, wherein good accessibility facilitates the work tobe carried out. Only with this construction, can more than four printingmechanisms be received in one satellite arrangement. Adjustments of thecassette systems or printing mechanisms in the service position are alsopossible during running production.

Essential to the design of the satellite printing machine is that it issuited for simple combination with a displaceable, inline furtherprocessing station. Servomotors are preferably combined withconventional gearing in this fashion, wherein the displaceability of thefinishing units is a requirement. An advantage of this processingconsolidation is the increased accuracy of the finished products andreduction of additional processing means.

There are conventional digital printing machines whose flexible use isoptimized through extension of the machine configuration with severalpaper feeder devices and sheet trays but which require a relativelylarge amount of space (large foot print) due to their horizontalarrangement and which require several feeder and delivery devices.

One machine concept is novel and considerably easier and compact, withwhich the so-called sheet trays are vertically arranged for only onesingle feeder and only one single delivery, with minimum machine floorspace (foot print).

In a further inventive embodiment (FIG. 8), the gripper transport devicecan be mechanically lowered into the cylinder to below the cylindersurface when it is not used for the sheet transport such that theillustrating cylinders can unwrap irrespective of the format withoutgripper openings or tensioning channels, or without upward/downwardmotion.

Also novel in sheet processing as offset rotation printing, is theinnovative arrangement of the gripper shaft which permits lowering(FIGS. 10 and 11) and also pivoting to facilitate exchange of tensionedprinting blankets (FIG. 12).

The gripper systems could be designed such that they can bepneumatically or electromagnetically lowered. The lowering mechanism ofthe grippers can also serve for adjustment to the variable thickness ofthe material to be printed.

In a further inventive embodiment, the satellite printing machine isconstructed such that at least the intermediate supports 2 a+2 b have aperiphery of the smallest common denominator of several standard formatse.g. B3, B2, and B1 to facilitate mass production. These cylinder headsare very advantageous for mass production but more importantly provide astandard imaging cassette which can be mass produced at little cost.

The patent document U.S. 2002/00980017 shows the use of digital printingmechanisms for front and back side printing of different constructions.A further inventive embodiment is the uniform construction of theimaging cassettes for both front and back side printing in that they orthe machine is/are prepared in terms of construction e.g. drive, tubeconnection etc. for mounting, from the drive side and also from theoperating side to permit uniform construction also for both front aswell as back side printing.

In the satellite printing machine, the printing mechanisms for front andback side printing can be sequentially disposed with or without surfacedrying. Moreover, one complete printing unit is installed per (process)color and therefore, the color copies are printed in the so-calledSINGLE SHOT and SINGLE PASS SYSTEM in front and back side printing. Atthe input and/or output of the counterpressure cylinders, severalvariants and additional steps can be integrated before and/or afterdigital printing e.g. in the cassette units 9 and 15 (FIG. 3) e.g. forconditioning, coating, lacquer application, special print, fixing(fusing), drying and subsequent moistening. In accordance with theinvention, a uniform system 21 is integrated for combined application ofprotective lacquer and silicon oil for fixing (fusing). Thecounterpressure cylinders 4 have a surface which rejects color or toner.One single feeder 6 and one single delivery 18 can exchange variousmaterial to be printed in the paper pile in an easy and non-stop fashionusing paper cassettes, so-called sheet trays. For optimum operatingease, the printing and conditioning systems are disposed in the cassetteinserts. This provides optimum accessibility to the working position 54within the machine frame and in the service position outside the machineframe, on the operating 55 and/or drive side 56.

The printing quality of digital printing and of conventional printingtechniques requires clean surfaces of the intermediate cylinders coatedwith an elastic material. The intermediate cylinder is exposed tosurface soiling through a mixture of i.a. paper dust and toner residues.The use of 2-fold cleaning systems is novel.

-   1. A system e.g. with electrostatic brushes which rotates against    the direction of rotation of the intermediate cylinders to remove    the toner residues.-   2. A cleaning system with brushes or blanket, which are enriched    with water for removing the paper dust residues.

A further inventive embodiment is a photo conductor drum/illustratingcylinder with bearer rings. Due to the gripper-receiving recess on theperiphery of the intermediate cylinder, optionally having tensioningchannels, the rotating printing process generates irregular pressureload which can produce stripes in the print. Mounting of the bearerrings on the photo conductor drum and the intermediate cylinder, whichare mounted with pretension, eliminates this irregular pressure load andobtains optimum printing quality. The illustrating cylinders, which areconstructed for rapid exchange, can be coated as a photo conductor drum.However, they are preferably designed for one-side quick dismounting ofthe bearer rings to facilitate replacement of the photo conductorsleeve. A further inventive embodiment of the digital printing mechanismis a construction which permits rapid exchange of the toner unit 53,including its color-carrying components. One particularly advantageouseffect of this innovative printing machine and method is theparticularly low energy consumption, which is estimated to be onlyapproximately 20% of the consumption of the conventional printingmachines with drives for 35 meters of length, intermediate and enddryers, and temperature-control systems for the printing mechanisms.

A further aspect of the invention is the integration of a coronatreating system in the machine to permit use of plastic materials and/ormetallized and/or sandwich materials without pre-treatment. Prior artdoes not permit integration in the sheet printing machine due to limitedspace conditions in sheet transfer systems through arrangement ofstaggered feeder, front lay mark and pivoting gripper.

A dryer 11 is provided on the delivery side. Further transfer drums (notshown) can be inserted between the two counterpressure cylinders. Achain transfer (not shown) could be inserted between the twocounterpressure cylinders e.g. for intermediate cooling.

The presented arrangement with up to approximately 10 printingmechanisms is to be considered as basic embodiment of this compactconstruction. If further printing mechanisms are required, individualposts with conventional and/or digital print could be placed upstream orwith a multi-color frame. Possible inline finishing (production) maynormalize the complete production of the finished products, which aree.g. punched, stamped, perforated, folded and cut.

The underlying purpose of the invention is achieved by a digitalprinting machine which comprises the features of claim 1.

Further details and advantageous effects of the invention can beextracted from the following description and the drawings which showembodiments of the inventive satellite printing machine.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a side view of the inventive satellite printing machine;

FIG. 2 shows a side view of the inventive satellite printing machinewith upper and lower intermediate cylinders;

FIG. 3 shows a side view with enlarged counterpressure cylinder withassociated pre-press and finishing cassette and inline furtherprocessing system;

FIG. 4 shows an enlarged sectional view of a cassette system forconditioning;

FIG. 5 shows a representation of one cassette system for illustration indifferent working positions;

FIGS. 6 and 7 each show a schematic illustration of the inventivesatellite printing machine with a drive concept in the region of thesheet delivery;

FIG. 8 shows a side view with intermediate cylinder with gripper system,shown in the 7 o'clock position;

FIGS. 9 through 13 show sectional views of the intermediate cylinders inthe region of the gripper transport system;

FIG. 14 shows a side view of the inventive satellite printing machine ofFIG. 2, however, with horizontal feed advance system with integrateddouble chamber for corona treatment on both sides of the substrate;

FIG. 15 shows a side view of an imaginary satellite-like sheet offsetprinting machine;

FIG. 16 shows a side view of an imaginary modular sheet offset printingmachine with 8 printing mechanisms in series construction;

FIG. 17 shows a side view of the feeder with adjacent pre-piling means;

FIG. 18 shows a side view like FIG. 3, however, shown in the so-called 7o'clock position, and reprinting system;

FIG. 19 shows a side view like FIG. 1, however, with advance system withintegrated corona treatment system with integrated turning drum systemand inline finishing unit;

FIG. 20 shows a side view of a satellite printing machine with centralcounterpressure cylinder with gripper transport system and rubberblanket cylinder which is format-dependent and has channels;

FIG. 21 shows a side view of the uniform intermediate cylinder forseveral standard formats;

FIG. 22 shows a side view of a digital printing machine with transferband;

FIG. 23 shows a side view of a digital printing machine with transferdrum or common photo conductor drum;

FIG. 24 shows a side view of a digital printing machine with formattedtransfer band;

FIG. 25 shows a view of an illustrating cylinder with bearer rings;

FIG. 26 shows a detailed view of FIG. 25.

FIG. 27 shows a detailed view of FIG. 26.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 shows a satellite printing machine, referred to with 1, with anapparently illogical combination of format-free printing mechanisms andformatted gripper transport systems, with a formatted intermediatecylinder 2 having rubber blankets and with a counterpressure cylinder 4which, relative to the direction of rotation D, has an upstream cleaningsystem R and seven format-free satellite printing mechanisms S formulticoloured, front side printing, with one formatted sheet feeder 6and a formatted delivery 18 both for the so-called sheet trays 19.

The printing sheets are transferred from the sheet feeder 6 to the firstprinting mechanism and optionally from printing mechanism to printingmechanism and from the last printing mechanism to the delivery pile 18using gripper technology which is integrated in a format-dependentmanner in the counterpressure cylinder channel or in a chain carrier.The separation between two adjacent gripper systems is therefore alwaysequal to the maximum printing format in the peripheral direction.

A cassette unit 21 is also shown for the combined application of siliconoil and protective lacquer. The drawing clearly shows that theillustrating cylinders 1 through 7, which are not restricted to aformat, have a considerably smaller diameter than the format-dependentlacquer or silicon application cylinders 21. The 7 o'clock position isnot shown herein.

The schematic illustration of the satellite printing machine 1 of FIG. 1uses sheets as the printing material which can be grasped in the regionof the supply cylinder 3, wherein the counterpressure cylinder 4 and thedelivery system 5 have gripper systems 14. The supply cylinder 3 has anupstream alignment table 7 which can be adjusted in the transversedirection, in height, in the supply direction and/or in an inclineddirection relative to the supply direction through conventional side andfront lay mark systems. It is also feasible to provide adjustment meanson the alignment table 7 (not shown in detail) for carrying out theabove-described changes in the supply direction of the printingmaterial. These adjustments can also be made during operation of thesatellite printing machine 1. The alignment table has vacuum transportbands and in these regions, the table has respective format-dependentshieldings to prevent energy loss (not shown).

The machine 1 is designed such that the supply cylinders 3, pressurecylinders 4, intermediate cylinders 2, illustrating cylinders 52(including toner unit 53) and delivery cylinders 5 can be radiallydisplaced via eccentric bushings (arrow Y) for adjustment, duringproduction, to different thicknesses of the material to be printed.Linear adjustment is also feasible.

In an embodiment which is advantageous for operation of the machine 1,the supply system 3 and the delivery system 5 are disposed above asupport plane at substantially the same height to define anapproximately horizontal operation plane. Additional units for inlinefinishing or further processing may be provided in the region of thedelivery system 5 and/or delivery chain 28 for further downstreamprocessing (FIG. 3) using further guidance of printing material in asupply line for lacquering, drying, embossing, punching and the like.These heights permit simple loading and unloading of the machine 1 fromthe floor.

The machine 1 is realized in such a manner that any printing methods canbe combined to maximally utilize the flexibility of the material to beprinted.

FIG. 2 is like FIG. 1 however having a second intermediate cylinder 2 band counterpressure cylinder 4 b, and also 2 cassette units 15 e.g. forfinishing.

FIG. 3 is like FIG. 1, however, with enlarged counterpressure cylinder 4for disposing cassette units for pre-press systems 9 and cassette unitsfor finishing systems 15.

The displaceable (arrow 6) inline further processing unit 66 is alsoshown. The figure clearly shows that the substrate sheet is completelyprinted before it is taken over by the delivery chain.

FIG. 3 also shows a device for finishing works, in particular forcutting or punching 35 and/or embossing and foil application 36 via arotation process, wherein the material to be printed 57 can be insertedin an advance direction D between two rotating processing rollers 33, 34and is processed while passing tool parts (not shown) acting in theworking gap, to separate the substrate into a waste part and a usefulpart.

The suction hood 69 disposes of the waste part in an upward direction.Disposal may also be effected via the inside of cylinder 70 or in adownward direction 71.

The delivery 67 may deliver finished products such as folding box blanksor finely cut-out sheets. The delivery 68 can deliver punched sheets orsheets with sections.

FIG. 4 shows the support of one cassette unit for finishing 15 in theregion of the machine frame. The cassette unit is thereby supported onrails 43 and 45 of respective side posts of the machine frame 41. Thecassette unit 15 can be displaced in a parallel manner on these rails.It is also feasible to displace each satellite printing mechanism 5together with these rails. In the embodiment shown, a linear ballbearing 41 or cam rollers 46 are provided for the respective rails (FIG.2) and the rail 43 has a lower traverse. For positionally accuratedisplacement of the cylinders, the two rails are connected via a supportbrace (44) such that they can be displaced next to the machine frame andcan be returned into the working position without any distortion.

The anilox roller 38 is also referred to as a screen or nap roller sinceit has a screen of laser-produced nap which absorbs more or less liquidin dependence on its size. The upstream chamber doctor 39 controls thecoated film and regulates the return motion. The anilox roller 38 can bequickly exchanged to permit coatings of different thicknesses. This alsoapplies for standard anilox rollers and also to photo conductor aniloxrollers.

The illustrated cassette units 51 of FIG. 5 each comprise anillustrating cylinder 52 and a (replaceable) toner supply unit 53. Afterlifting (Y) from their printing position (FIG. 4 and 5) on theintermediate cylinder 2, the cylinders in the cassette units 15 can bedisplaced into a service position without requiring tilting of thecassette unit. This increases the position stability of the cassetteunits which permits printing with little vibration to eliminate printingdistortions.

FIG. 5 also shows the cassette positions in the machine frame, referredto in general with 41, wherein the cassette unit 51 is shown in themedium region, i.e. working position 54 and the right-hand side of theillustration shows that the cassette unit can be displaced parallel tothe axis of rotation of the intermediate cylinder 2 into a lateralservice position toward the operator side 55, next to the machine frame(arrow K, FIG. 5). The cassettes are also shown in a service position atthe drive side 56.

The inventive cassette concept of the satellite printing machine 1permits up to ten associated satellite printing mechanisms for frontside printing S and up to ten satellite printing mechanisms for the backside W which may be directly adjacent to each other, in compactconstruction.

The toner cassette 53 with color-carrying part is constructed to bereplaced for convenient color change, e.g. for customer-specific colors.

The photo conductor drum or illustrating cylinder 52 are alsoconstructed for quick exchange.

FIGS. 6 and 7 show a schematic illustration of a drive concept in theregion of the printing machine 1, the delivery system 18 and the device36. Two servo drive motors 26 and 27 are provided for securing asynchronous drive, each with a contact-free gearing 30, wherein thegearings also engage without contact at a constant separation 31 duringthe drive phase. The teeth abut only when a control error, e.g. asoftware error, could produce an undesired overload of the system,requiring immediate switching off of the drive moment. This gearing 30protects the system from damage, in particular the gripper systems, in astraightforward manner. The play-free gearing 32 provides synchronousmotion of the male mold punching cylinder 34 and female mold punchingcylinder 33.

FIG. 8 shows the satellite printing machine of FIG. 1, in an inventiveembodiment having an additional lower intermediate cylinder 2 bcomprising rubber blankets, with an associated cleaning cylinder 6 andseven satellite printing mechanisms W for multi-color reprinting, viewedin the direction of rotation D, behind the delivery system 5 and beforethe supply cylinder 3. The intermediate cylinders have differentcircumferences, e.g. for receiving conditioning cassettes.

A pre-print cassette 9 is disposed before the printing point 13 of thetwo intermediate cylinders e.g. for fixing or conditioning and acassette 15 is disposed after the printing point 13 e.g. for finishing(e.g. application of lacquer). In the above-described arrangement ofFIG. 8, the back side print is effected in the region between the supplycylinder 3 and the contact point or printing point 13. The grippers arelowered in the region 75.

FIGS. 9, 10, 11, 12, and 13 show a section with gripper systemsillustrating the gripper support 64, material to be printed 57,tensioned rubber blanket 58, cylinder body 59, tensioning strip 60 andglued rubber blanket 65. A rubber blanket tensioning system 90 withtensioning strip 60, tensioning slit 62 and tensioning direction 63 andgripper back 61 are also shown.

FIG. 9 shows the gripper system in its working position for substratetransport 57 with tensioned printing blankets 58, wherein the rubberblanket is tensioned with two tensioning shafts 90.

FIG. 10 corresponds to FIG. 9, however, the rubber blanket is clampedwith the tensioning strip 60 and tensioned with the clamping device 90.

FIG. 11 shows the gripper system in a lowered position for passage ofthe illustrating cylinders. The gripper backs 61 are now below theunwinding surface, whereby the illustrating cylinders can be unwoundunder pressure without gripper openings or gripper channels on theelastic printing blanket without any risk of damage.

FIG. 12 shows the gripper system in the pivoted-down position to enableexchange of the tensioned printing blankets 58.

FIG. 13 shows the gripper system in connection with glued printingblankets 65 which conventionally require no tensioning device.

The gripper openings towards the gripper supports 64 in the printingblankets permit function of the gripper systems when the printingblankets are tensioned (not shown).

Tensioning strips 60 and tensioning slits 62 or tensioning shafts 90with tensioning channels facilitate support for tensioning orre-tensioning of the printing blanket.

FIG. 14 shows a satellite printing machine, referred to in total with 1,basically like FIG. 2 which shows horizontal sheet insertion with sidemark 23 and advance roller 24 and double chamber 25 for surfacefinishing systems on one or both sides, e.g. for corona treatment. Thischamber could be loaded with vacuum or compressed air to support and/orenhance the sheet guidance. The cylinder arrangement corresponds to theso-called 7 o'clock position.

FIG. 15 shows a schematic printing machine of satellite constructionbased on FIG. 1 of U.S. Pat. No. 5,036,763. The schematic printingmachine is extended to 2×7 printing mechanisms for Hi-Fi prints. Thedimensions indicate that even the half-format (B2) of this machine wouldhave unrealistic operating dimensions compared to FIG. 2. The so-calledS-winding of the stop drum feed configuration 92 also fails to meet therequirements of minimum paper travel.

FIG. 16 also shows a schematic printing machine of modular, seriesconstruction. A schematic configuration like FIG. 2 with 2×7 colors andlacquer mechanisms and inline further processing would producecompletely unrealistic dimensions and therefore non-economicalinvestment for a printing machine.

FIG. 17 shows a sheet feeder 6 with neighboring pre-stacking means 76.An operator can load one of the sheet trays (cassette with material tobe printed) 19 during production, which can be adjusted to his/herheight 77 and can then be positioned automatically by means of lateraldisplacement 78 in the feeder when the order changes. This permits rapidchange requiring only one expensive suction head 79. One furtheradvantage is that the length of the machine is not extended.

FIG. 18, similar to FIG. 3, also shows the so-called 7 o'clockarrangement 49, wherein the sheet is completely printed before it isfurther transferred by the delivery chain 14. The back side printingarrangement is also shown with one cleaning cassette 72 and one printingmechanism cassette 73. The counterpressure cylinder is coated withrubber blanket segments 74 and the grippers are withdrawn in the region75.

FIG. 19 is like FIG. 1 with a conventional turning drum system withtransfer drum 81, turning drum 82 and storage drum 83.

For a turning operation, the feeder is controlled such that no sheetsare supplied when some sheets pass through the printing machine in asecond run. The grippers in the counterpressure cylinder areprogram-controlled such that the sheets are automatically taken over bythe delivery chain or not. This turning technology is prior art,however, in this embodiment the format is fixed. The fact that thetransfer cylinder 81 is driven by a servo motor at different speedspermits processing of different formats in the peripheral direction.

An inline finishing unit 50 is also shown e.g. for folding orbook-binding. The sheet is transferred precisely with gripper technology29. Advantageously, this unit can be displaced.

FIG. 20 shows a satellite printing machine 84 with a central counterpressure cylinder and having gripper systems. The substrate sheetsurrounds the counterpressure cylinder and is imaged with partial colorin each digital printing mechanism, i.e. not in single shot. Theillustrating cylinders or the photo conductor drums are smaller than theprinting length and printing is effected indirectly via format-relatedrubber blanket cylinders, in this example of a diameter of only 129.36mm or not even A3 upright format. The photo conductor-drum cannot printdirectly since it would be damaged by the projecting gripper backs ofthe grippers, which are mounted in the central counterpressure cylinder.

8 digital photo conductor drums are shown for e.g. a 7-color print withintegrated lacquer application. The periphery of the format-relatedrubber blanket is 24.

FIG. 21 schematically shows an intermediate cylinder (2 a and 2 b) witha smallest common denominator of a diameter of e.g. 690 mm, whichproduces, with corresponding division by ¼ the B3 square format, by ½the B2 portrait format, and by ½ but with double width the B1 landscapeformat.

This single periphery permits use of identical imaging cassettes whichare disposed around the intermediate cylinder providing particularlyinexpensive series production.

FIG. 22 shows a digital printing machine 85 for duplex printing, whereinthe intermediate cylinders provided with rubber blankets have anupstream transfer band 88 for accepting the individual colors.

Imaging of the transfer band 88 can be effected through contact, e.g.pressure or contact-free, e.g. through spraying or injection. The twointermediate cylinders 2 provided with rubber blanket/s includingchannels permit sheet transport by grippers since the grippers wouldotherwise damage the transfer band through direct contact due to theprojecting gripper backs. The intermediate cylinders 2 are disposed suchthat transfer is effected when the printed image is completely printed.

FIG. 23 shows a digital duplex printing machine 86 (like FIG. 22),wherein a transfer drum 81 or a common photo conductor drum 81 forcollecting the individual colors is disposed upstream of theintermediate cylinder 2, which is provided with rubber blankets.

FIG. 24 shows a digital printing machine 87 for duplex printing, whereinthe transfer band 88 is format-dependent and the counter pressurecylinder 4 has sheet-holding grippers, with the gripper-receiving recess(not shown) being provided on the periphery of the rubber band.

FIG. 25 shows a digital printing machine with 2 printing mechanisms 1(as in FIG. 1) with intermediate turning system 81, 82, 83. Two timesseven colors can be printed on the first side or seven colors on each ofthe first and second sides.

FIG. 26 shows an illustrating cylinder 52 with bearer rings 89 on bothsides which can be dismounted quickly on one side of the illustratingcylinder (arrow Z).

The intermediate cylinder 2 is also shown with bearer rings 89 andtensioning device for the rubber blanket 90.

FIG. 27 shows a detail of FIG. 26 with rubber blanket 58 and photoconductor coating 91 or photo conductor sleeve 91.

LIST OF REFERENCE NUMERALS

-   1. satellite printing machine-   2. intermediate image transfer cylinder with channels-   3. supply cylinder with gripper strip-   4. counterpressure cylinder with gripper-   5. delivery cylinder with gripper-   6. sheet feeder-   7. alignment table-   8. swinging gripper-   9. cassette unit for pre-print-   10. coating system-   11. dryer-   12. printing blanket tensioning system-   13. printing point-   14. gripper system-   15. cassette unit e.g. for finishing-   16. fixing system (format-related)-   17. sunk gripper system-   18. sheet delivery-   19. printing material cassette-   20. surface area for fixing-   21. cassette unit silicon and lacquer coating-   22. gripper opening or tensioning channel-   23. side lay mark-   24. advance rollers-   25. double corona chamber-   26. servo drive printing machine-   27. servo drive finishing station-   28. delivery chain-   29. chain wheel delivery-   30. contact-less gearing-   31. without gearing-   32. gearing connection without play-   33. female mold-   34. male mold-   35. punching and grooving device-   36. embossing and foil device-   37. side post cassette-   38. anilox illustrating cylinder-   39. chamber doctor-   40. lacquer application roller-   41. side post of the machine frame-   42. open linear ball bearing-   43. support rail with traverse-   44. support strut-   45. support rail-   46. cam roller-   47. gripper opening-   48. tensioning channel-   49. 7 o'clock position-   50. inline finishing unit e.g. for folding-   51. cassette unit for imaging-   52. illustrating cylinder-   53. toner supply unit-   54. cassette in working position-   55. cassette in service position towards the operator side-   56. cassette in service position towards the drive side-   57. material to be printed-   58. tensioned rubber blanket-   59. cylinder body-   60. tensioning strip.-   61. gripper back-   62. tensioning slit-   63. tensioning direction-   64. gripper support-   65. glued rubber blanket-   66. inline further processing-   67. delivery blanks-   68. delivery punched sheets-   69. disposal in upward direction-   70. disposal towards the cylinder interior-   71. disposal in downward direction-   72. cleaning cassette, back side print-   73. satellite printing mechanism for second print-   74. rubber coated counterpressure cylinders-   75. sunk gripper zone-   76. pre-stacking means-   77. height adjustment-   78. lateral displacement-   79. suction head-   80. turning drum system-   81. transfer drum-   82. turning drum-   83. storing drum-   84. printing machine with central counterpressure cylinder-   85. printing machine with transfer band-   86. printing machine with transfer drum or common photo conductor    drum-   87. printing machine with format-related transfer band-   88. transfer band-   89. bearer ring-   90. tensioning device rubber blanket-   91. photo conductor coating or photo conductor sleeve-   92. stop drum abutment-   C arrow paper transport direction-   S satellite printing mechanisms for front side print-   D direction of rotation in the cassette-   G arrow displacement finishing station-   W satellite printing mechanisms for back side print-   K arrow lateral adjustment in cassette-   R cleaning systems in cassette-   Y arrow radial printing feed adjustment-   V pre-finishing/lacquer application format-free-   Z arrow dismounting direction bearer ring

1. A digital printing machine for printing a sheet, the machinecomprising: at least one digital printing mechanism comprising at leastone illustrating cylinder having free format in a peripheral direction;at least one format dependent intermediate image transfer cylindercooperating with a respective one of said at least one digital printingmechanism for indirect printing, said intermediate cylinder being atleast partially covered with an elastic material for image transferunder pressure onto the sheet, a periphery of said intermediate cylinderhaving at least one recess; a counterpressure cylinder cooperating withsaid intermediate cylinder; and at least one gripper cooperating withsaid counterpressure cylinder for holding the sheet, said at least onegripper having mechanical fingers structured and disposed for acceptancewithin a respective one of said at least one recess of said intermediatecylinder.
 2. The digital printing machine of claim 1, further comprisinga transfer band and/or a transfer cylinder disposed between said digitalprinting mechanism and said intermediate cylinder.
 3. The digitalprinting of claim 1, wherein at least four digital printing mechanismsare provided for at least one of front and back side printing.
 4. Thedigital printing machine of claim 3, wherein said digital printingmechanisms are disposed like satellites about one of said intermediatecylinder, a transfer band, and a transfer cylinder.
 5. The digitalprinting machine of claim 4, comprising satellite printing mechanismsand conditioning cassettes each form a cassette-shaped construction unitwhich can be displaced towards an operating and/or drive side of themachine from a working position into a service position.
 6. The digitalprinting machine of claim 1, wherein each one of said at least onedigital printing mechanisms cooperates with its own said at least oneintermediate cylinder.
 7. The digital printing machine of claim 1,comprising digital printing mechanisms for front and back side printingwith a same construction.
 8. The digital printing machine of claim 1,further comprising an anilox type illustrating cylinder having chamberdoctors for applying powder or liquid toner.
 9. The digital printingmachine of claim 1, wherein for changing a format, said intermediatecylinder and said counterpressure cylinder are structured fordisplacement either individually or as an assembly, wherein said atleast one digital printing mechanism is independent of format and saidintermediate cylinder is designed for several standard formats.
 10. Thedigital printing machine of claim 1, wherein said intermediate cylinderis a rubber blanket cylinder.
 11. The digital printing machine of claim10, wherein said intermediate cylinder has gripper recessesaccommodating tensioning systems for tensioning and re-tensioning ofprinting blankets.
 12. The digital printing machine of claim 1, whereinsaid illustrating cylinder has bearer rings which can be quicklydismounted for rapid replacement of illustrating sleeves.
 13. Thedigital printing machine of claim 1, further comprising aformat-variable sheet turning device having at least one transfercylinder which can be operated at different speeds.
 14. The digitalprinting machine of claim 1, further comprising several printing systemshaving differing printing methods without format and/or withpredetermined format and structured for use with integratedconditioning, coating, fixing, drying and renewed moistening devices.15. The digital printing machine of claim 1, wherein said intermediatecylinder comprises sinking grippers.
 16. The digital printing machine ofclaim 1, wherein said illustrating cylinder has a smaller circumferencethan a maximum printing format in a peripheral direction of the printingmachine.
 17. The digital printing machine of claim 1, whereinmulticolored image transfer is carried out in a single shot printing gaprun and in a single pass machine run for at least one of a front and aback side print.